1. Field of the Invention
The present invention relates to ball joint assemblies, and more particularly to structure of a sealing cap in a ball joint assembly.
2. Description of the Prior Art
Spherical or ball joints intended for various industrial applications, such as steering and suspension systems of automotive vehicles, need a sealing system to prevent impurities, such as road dirt, sand and water, penetrate in its interior. Consequently, the presence of impurities between the frictioning parts of the ball joint assembly tends to cause a premature wear of its components and affects the operation of the ball joint assembly.
The ball joint assemblies are well known in the prior art. The typical ball joint assembly normally comprises a ball rod having a substantially spherical ball member at its one end and an elongated substantially cylindrical shank member at its other end. The ball member of the ball rod is coupled to a single or divided bearing and is housed within an interior of a ball joint casing. The ball joint casing has an opening through which the ball portion of the ball rod and the bearing are mounted within the ball joint casing. The ball member of the ball rod is sealed within the ball joint casing by a flexible sealing cap fixed to the casing so as to prevent the penetration of impurities into the interior of the joint casing.
Usually, the sealing cap is made of rubber, or any other similar elastic material. The sealing cap has two open ends. A first end having an opening of a bigger diameter is coupled to an external surface of the casing, and a second end having an opening of a smaller diameter is mounted about the shank member of the ball rod. The ends of the sealing cap are coupled to the casing and the shank member of the ball rod by means of corresponding straining rings, such as C-rings, pressing the ends of the sealing cap against the external surface of the casing and the shank member, respectively.
This way of coupling of the sealing cap to the shank member of the ball rod, however, has proven itself inefficient due to some undesirable effects, related to the angular movement of the ball rod in its maximum limits, and the fact that the damage the sealing cap may occur during the mounting of straining rings on the ends thereof.
The present invention provides a novel sealing cap for a ball joint assembly for use in a motor vehicle. The spherical joint assembly in accordance with the present invention comprises a ball rod having a ball member at its one end and an elongated shank member at its other end, a bearing receiving the head member of the ball rod, a casing housing the bearing, and a sealing cap having a first end secured to the casing by means of a straining ring, and a second end mounted about the shank member. The shank member of the ball rod is provided with an annular crown member and an annular flange member axially spaced from the crown member. The crown member and the flange member form an annular sealing seat receiving the second end of the sealing cap. The second end of the sealing cap is provided with a sealing bulge and a flexible sealing lip extending from said sealing edge, so that when the second end of the sealing cap is mounted over said sealing seat of said shank member, the sealing lip deforms and bends over towards the sealing edge.
Therefore, the sealing cap of the present invention substantially improves sealing of the ball joint assembly over the prior art, eliminates the second straining ring used for coupling the second end of the sealing cap to the shank member of the ball rod, provides more reliable sealing, and makes the process of assembling the ball joint assembly easier and less laborious.